I've used Virgin pre-paid and it's no different than any of the other pre-paid carriers, as far as I can tell (besides being cheaper).
That being said, keep in mind that they try to have a very hip-hop feel. When you call to top up, the recorded voice that guided you through everything is a little "ghetto" and even uses some street slang, and much of their literature and signage reflects this attitude.
Gets a little annoying after a while...